JPH1122906A - Bracing for heating tube panel and exhaust-heat recovery boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep an exhaust-heat recovery boiler, which is operated by repetition of starting and stopping everyday, from making noise at a sliding part at which the header of heating tubes is tied in with the boiler casing. SOLUTION: In an exhaust-heat recovery boiler, an upper header of panels of heating tubes 16 is supported on a casing by a hanging device and as for the lower header 17, a bracket 22 on the side of a lower header for the casing 12 and a bracket 26' on the side of the casing are connected with a link 30 with the intermediary of freely rotatable pins 28, 29. In doing this, agreement in direction in which a piping reaction of a connecting pipe 32 connected with the header 17 acts toward the header 17 and in the direction of expansion in which a connection part (pin 28) on the side of the casing 12 of the link 30 is used as an expansion standard enables absorbing through the rotation of the link 30 the expansion under heat of a heating tube, etc., when the boiler is in operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal exhaust heat recovery boiler and, more particularly, to a steadying device for a header portion.

[0002]

2. Description of the Related Art A high-efficiency combined cycle power plant first generates electric power by a gas turbine, collects heat in exhaust gas discharged from the gas turbine in a waste heat recovery boiler, and uses the waste heat recovery boiler. The generated steam drives a steam turbine to generate power.

[0003] This combined cycle power plant has the advantages of not only high power generation efficiency but also high load responsiveness, which is a characteristic of gas turbines, and can sufficiently cope with a sudden increase in power demand. FIG. 3 shows a structure of a conventional exhaust heat recovery boiler that recovers heat of turbine exhaust gas exhaust gas.

In FIG. 3, exhaust gas G of a gas turbine introduced into an exhaust heat recovery boiler includes a superheater 1 and a high-pressure evaporator 2.
Through the denitration apparatus 3 and the nitrogen oxides (N
Ox) is removed. Subsequently, the exhaust gas is discharged out of the system through the high-pressure evaporator 4, the high-pressure economizer 7, the low-pressure evaporator 8, and the low-pressure economizer 11. The high-pressure main steam S ₁ and the low-pressure main steam S ₂ generated during this time are used as a power source of a steam turbine (not shown) and an in-plant heat source.

[0005] In addition to the above equipment, the exhaust heat recovery boiler includes a high pressure drum 5 and a high pressure downcomer 6 connected to a high pressure evaporator 4, and a low pressure drum 9 connected to a low pressure evaporator 8 and a low pressure economizer 11. And a low pressure downcomer 10 and the like.

FIG. 4 (a view taken along the line AA in FIG. 3) shows a supporting device for the heat transfer tubes 16 in the heat recovery steam generator. The exhaust heat recovery boiler has a high-temperature duct (flue) body whose casing 12
And a heat insulating material 13 lined inside the casing 12. In order to prevent the casing 12 from being greatly deformed by the furnace pressure acting on the duct body, the casing 12 is provided with a support member 1 for supporting the periphery thereof.
4 reinforced.

The duct body contains a heat transfer tube panel (heat transfer tube group) constituted by an upper header 15, a heat transfer tube 16 and a lower header 17. The upper header 15 shown in FIG. 4 is suspended from the casing 12 by a suspension member 27, and the heat transfer tube group of this structure is of a suspended type. FIG. 5 is a view taken in the direction of arrows AA in FIG.

The procedure for assembling the heat transfer tube group supporting device is as follows. First, on the lower side of the lower header 17 of the heat transfer tube 16, a lug 23 (23a to 23a
23b) is attached. So as to sandwich this lug 23,
A header-side mounting bracket 25 is provided and joined with a pin 24. The pin holes of the lugs 23a provided in the lowermost headers of the foremost stream and the laststream in the exhaust gas flow direction are round holes to support the weight of the header-side mounting bracket 25. The pin hole of the lug 23b provided on the shifter 17 is a long hole elongated in the vertical direction. This is because each of the lower headers 17 has a relative difference in vertical extension, so that the long hole absorbs the relative difference in expansion.

Next, a post 22 is attached to the inside of the casing 12 from the support beam 21 attached to the outer surface of the casing 12, and the post 22 is sandwiched in the exhaust gas flow direction.
It is mounted and supported by a bracket 26 provided on a lower header-side mounting bracket 25, and is attached to a structure capable of absorbing a vertical expansion / contraction amount of a header portion of each heat transfer tube group.

[0010]

As shown in FIG. 5, the heat transfer tube group supporting apparatus in the conventional heat recovery steam generator has a lower pipe-side mounting bracket 25 and a post 22 which is a casing 12-side mounting bracket. In the structure, the post 22 projecting from the casing 12 side is sandwiched between two brackets 26 on the header 17 side to support the heat transfer tube group.

However, since the header 25 is attached to the casing 12 and the header 17 because the fitting 25 moves vertically due to thermal expansion when the boiler is started and stopped.
The connecting portion on the side slides, and the reaction force of the connecting pipe 32 connected to the header 17 also acts at the same time, and abnormal noise is generated when the boiler is started and stopped in the sliding portion of the connecting portion.

In order to prevent the generation of abnormal noise in the sliding portion of the connecting portion, the connecting pipe 32 is actually arranged with a flexible pipe so that a large pipe reaction force does not act on the header 17 side. I have.

However, even when the boiler is started and stopped, the thermal expansion movement of the header 17 in the vertical direction causes
At the joint between the header 17 side and the casing 12 side, there is a problem that abnormal noise is generated continuously for a certain period of time.

An object of the present invention is to provide a waste heat recovery boiler which is repeatedly started and stopped every day and which does not generate abnormal noise in a sliding portion of a joint between a heat exchanger tube side and a boiler casing side. To provide.

[0015]

The above object of the present invention is attained by the following constitution. In an exhaust heat recovery boiler that is built into a casing that forms a flue for exhaust gas from a gas turbine and has a header at the top and bottom of a vertically arranged heat transfer tube panel, the upper header of the heat transfer tube panel is suspended. The lower header is a steadying device for a heat transfer tube panel of an exhaust heat recovery boiler, in which a lower header and a mounting bracket on the casing are connected to the casing by a link mechanism.

The link mechanism between the lower bracket and the casing-side mounting bracket of the present invention comprises a link having both ends rotatably mounted on both of the mounting brackets. A connection portion between the mounting bracket and the link mechanism can be used as a starting point of thermal expansion of the link.

At this time, both the lower bracket fitting and the casing-side support bracket are connected by a link via a pin,
Further, it is desirable that the direction in which the pipe reaction force of the connecting pipe connected to the header acts on the header side coincides with the extension direction based on the thermal expansion of the link at the connection portion of the mounting bracket on the casing side of the link mechanism.

When the lower bracket and the casing are connected to each other by a ring mechanism, the amount of movement of the heat transfer tube group caused by the vertical thermal expansion of the heat transfer tube group generated when the boiler starts and stops, and By the rotation of the link mechanism, the amount of thermal expansion due to the gas temperature of the link itself or the like based on the position of the connection portion with the link mechanism on the side can be absorbed.

Thus, according to the present invention, there is no sliding part at the joint between the lower header-side fitting and the casing-side fitting in the structure of the conventional exhaust heat recovery boiler shown in FIG. When starting and stopping,
No noise is generated at the joint between the header side of the heat transfer tube and the boiler casing side.

In addition, since the header moves slightly in the gas flow direction during the operation of the boiler due to the rotation of the link mechanism, the reaction force of the connecting pipe connected to the header is greatly reduced. There is also an advantage that the configuration in which the pipe is arranged in a flexible piping arrangement can be simplified. The present invention also includes an exhaust heat recovery boiler provided with the above heat transfer tube panel steady rest device.

[0021]

Embodiments of the present invention will be described with reference to the drawings. The configuration of the exhaust heat recovery boiler shown in FIG. 3 is common to the present invention, and includes a superheater 1, a high-pressure evaporator 2, a denitration device 3, a high-pressure evaporator 4, a high-pressure economizer 7, a low-pressure evaporator 8, and Heat transfer tube groups (heat transfer tube panels) constituting the low-pressure economizer 11 are arranged in a vertical direction. FIG. 1 is a partial cross-sectional view of a connecting portion between the lower header 17 of the group of heat transfer tubes 16 and the casing 12.
A communication pipe 32 is connected to the lower header 17, and through the communication pipe 32, the steam drums 6 and 9 or the downcomers 6 and 10 are connected.
And other devices or heat transfer tube panels are connected before and after.

The lower header 17 and the casing 1 shown in FIG.
The coupling mechanism with the two-side mounting bracket shows a steadying structure on the lower header 17 side when the upper header (not shown) of the heat transfer tube panel is suspended from the casing. FIG. 2 is a view for explaining the operation of the connecting mechanism shown in FIG. 1 when the boiler is operating or stopped.

The steadying structure on the side of the lower header 17 will be described with reference to FIG. The lower end of the heat transfer tube 16 is connected to a lower header 17, and the lower header 17 is fitted with a lug 23 oriented flat in the exhaust gas flow direction. This lug 23
Is provided so that the lug 23 is sandwiched between the lug 23 and the mounting bracket 25. As described with reference to FIG. 5, the pin holes of the lugs 23 a provided in the lowermost headers of the foremost stream and the last stream in the exhaust gas flow direction are round holes, and support the own weight of the header-side mounting bracket 25. The pin hole of the lug 23b provided in the lower header 17 of the heat transfer tube group of each section is a vertically elongated hole (an oval hole or a groove-shaped elongated hole). The target elongation difference is absorbed by the elongated hole. Mounting bracket 2 on lower header side
5 is provided with a bracket 26 '.

On the other hand, a post 22 is attached to the inside of the casing 12 from the support beam 21 attached to the outer surface of the casing 12, penetrating the heat insulating material 13. Then, a pin hole is provided in each of the post 22 on the casing 12 side and the bracket 26 'on the header 17 side, and both are connected by the link 30 via the pins 28 and 29, respectively.

Also, a casing side mounting bracket (post) 2
The position of the second pin 28 is defined as the heat expansion base point of the link 30 itself, and the link 30 based on the gas temperature inside the exhaust heat recovery boiler is used.
And the direction in which the pipe reaction force p (FIG. 2) during operation of the connecting pipe 32 connected to the header 17 acts on the header 17 in the same direction.

Thermal expansion movement of the header 17 generated when the boiler starts and stops, and the casing 1
The rotation of the link 30 absorbs the thermal expansion caused by the gas temperature in the furnace of the link 30 itself, which is based on the pin 28 of the mounting bracket (post) 22 on the second side.

This will be described with reference to FIG. Casing 1
Pin 28 of mounting bracket (post) 22 on two sides (see FIG. 1)
Is the thermal expansion base point, but when the boiler is stopped, the horizontal mounting length of the link 30 between the position b of the pin 29 and the position a of the pin 28 of the bracket 26 '(see FIG. 1) on the header 17 side is shown. However, since the pipe reaction force p acts on the connecting pipe 32 at the start of the operation of the boiler and there is a thermal expansion action in the vertical direction of the header 17, the link 30 is angled around the position of the pin 28. Rotate by d, link 3
A horizontal displacement e of 0 occurs. Furthermore, since the link 30 has thermal expansion, a horizontal shift f of the link 30 is added to that extent. As a result, the pin 29 of the bracket 26 'on the header 17 during the boiler operation moves to the position g, and the position g is displaced in the vertical direction h from the position b of the pin 29 when the boiler is stopped.

Further, since the link 30 is rotatably installed, the header 17 can be moved slightly in the gas flow direction, and the connecting pipe 32 connected to the header 17 can be moved in the opposite direction. The force acting on the header 17 side is greatly reduced.

[0029]

According to the present invention, the generation of abnormal noise at the joint between the header side and the boiler casing side can be prevented by absorbing the thermal expansion caused by the heat transfer pipe header generated at the time of starting and stopping the boiler. Lost.

[Brief description of the drawings]

FIG. 1 is a view showing a steadying structure of a connecting portion between a heat transfer tube header and a casing of an exhaust heat recovery boiler of the present invention.

FIG. 2 is a view for explaining the operation of the connecting mechanism shown in FIG. 1 when the boiler is operating or stopped.

FIG. 3 is a cross-sectional view of a horizontal heat recovery steam generator to which the present invention is applied.

FIG. 4 is a cross-sectional view of an exhaust heat recovery boiler having a conventional structure.

FIG. 5 is a diagram showing a steadying structure of a connecting portion between a header of an exhaust heat recovery boiler and a casing in a conventional structure (A in FIG. 4).
-A arrow view).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Superheater 2 High pressure evaporator 3 Denitration device 4 High pressure evaporator 5 High pressure drum 6 High pressure downcomer 7 High pressure economizer 8 Low pressure evaporator 9 Low pressure drum 10 Low pressure downcomer 11 Low pressure economizer 12 Casing 13 Heat insulation material 14 Supporting member 15 Upper header 16 Heat transfer tube 17 Lower header 21 Support beam 22 Post 23 Lug 24 Pin 25 Lower header-side mounting bracket 26, 26 'Bracket 27 Suspension member 28, 29 Pin 30 Link 32 Connecting pipe

Claims (4)

[Claims] An exhaust heat recovery boiler which is built in a casing forming a flue for exhaust gas from a gas turbine and has a header at an upper portion and a lower portion of a vertically disposed heat transfer tube panel. An upper heat collector boiler is supported by a casing by a suspending device, and the lower heat collector is connected to the casing by a mounting mechanism on a lower head side and a mounting part on a casing side by a link mechanism. Heat tube panel steady rest device. 2. The link mechanism between the lower header-side mounting bracket and the casing-side mounting bracket includes a link having both ends rotatably mounted on both of the mounting brackets. Sway stabilizer for heat transfer tube panel of waste heat recovery boiler. 3. The extension direction of the link mechanism starting from the connecting point between the casing side mounting bracket of the lower header and the link mechanism as a starting point of thermal expansion, and the pipe reaction force of the fluid flow passage connecting pipe connected to the lower header. The steadying device for a heat transfer tube panel of an exhaust heat recovery boiler according to claim 2, wherein directions acting on the lower header side are matched. 4. An exhaust heat recovery boiler comprising the heat transfer tube panel steady rest device according to claim 1.